The present invention relates generally to mineral separator systems and, more particularly, to the removal of non-magnetic conductor and non-conductor particles from a mineral bearing pulp fluid, the fluid being either a liquid or a gas.
The methods of recovery of a desired mineral from a mined mineral bearing pulp containing contaminants vary widely, even in the recovery of a particular mineral. These methods range from simple methods, such as panning for gold, to elaborate methods, such as physical separation processes, hydrometallurgical processes and pyrometallurgical processes. Extraction of ferromagnetic substances with the use of magnets is known in the art. Processes that separate out non-ferromagnetic substances by the use of magnets is not known in the art.
An art that can be considered to be related to mineral recovery is the recovery of municipal "waste" for recycling. One method known in this art involves the steps of shredding the waste and classifying the shredded waste into light and heavy fractions, each having therein items suitable for recycling, with the heavy fraction including, among other substances, ferromagnetic and non-ferromagnetic metals. The ferromagnetic metals can be extracted by conventional means, such as by the use of electromagnets. A method using magnets in the recovery of non-ferromagnetic materials from waste is described in U.S. Pat. No. 4,003,830 issued to Ernst F.R.A. Schloemann. This patent describes material separating apparatus for directing non-ferromagnetic conductor materials into a sliding stream and steady-state magnet means that establish in the path of the stream a series of oppositely directed magnetic fields that induce in the conductor non-ferromagnetic materials eddy currents that draw the associated conductor materials laterally out of the stream, thus isolating them from the non-conductors.
A problem relating to the apparatus taught by Pat. No. 4,003,830 is that the stream of materials is substantially a flat or planar stream. Such an orientation is necessary since a flat or planar row of magnets is used, and the conductive materials must intercept the curved alternate fields of magnetic force before eddy currents are set up in the conductive non-ferromagnetic conductor materials to be extracted. Thus, only a solid stream can be used, for a fluid stream would by nature be a three-dimensional stream. Accordingly, a pulp fluid could not be used in the apparatus described in this patent. Ferromagnetic conductors cannot be separated by this teaching because of the use of curved magnetic fields in the apparatus. Also, it is noted that semiconductor non-ferromagnetic materials cannot be recovered by the Schoelmann apparatus. In addition, the force of gravity is not a factor in the recovery of the non-ferromagnetic materials.
Another patent that teaches a method for the recovery of conductive, non-ferromagnetic fragments in waste material by use of a magnetic field is U.S. Pat. No. 4,083,774, granted to Jack A. Hunter. Hunter teaches the use of a magnetic field across the path of moving waste fragments with the conductive fragments generating eddy currents and resulting drag forces proportional to the conductivity of each conductive fragment so that different types of materials have differing descent trajectories into successively positioned zones relating to varying drag forces and varying densities.
A problem with the apparatus of Pat. No. 4,083,774 is that the field is rectilinear, that is, the magnets do not generate a field except one laterally between one another. This arc of magnetic force between adjacent magnets must be intercepted by the conductive fragments in a manner similar to the Schloemann apparatus. It is apparent that a three-dimensional fluid-occupied chamber having cross-magnetic fields is not possible in the Hunter teaching. For this reason, the force of gravity as a force utilized in the separation of the conductive non-ferromagnetic particles from the non-conductive particles is not found in Hunter. It is also noted that Hunter does not assume the presence of non-conductive materials. This is important, for it is a key factor of the problem to be solved in the extraction of minerals in mining procedures. Finally, Hunter does not deal with semiconductors.
An additional patent relating generally to the moving of electrically conductive non-magnetic components of waste material in U.S. Pat. No. 3,824,516 issued to Sander Benowitz. Eddy forces in conductor materials are described. This invention, however, relates to the handling and movement of conductive, non-magnetic materials, not the separation of conductive, non-magnetic materials from non-conductive materials.
A patent describing the separation of electrically conducting particles from mixtures containing electrically non-conductive particles by conveying the mixture through an angularly oriented magnetic field is described in U.S. Pat. No. 4,277,329 issued to Patrick E. Cavanagh.